Endodontic operating and sealing method and apparatus therefor

ABSTRACT

An endodontic operating and sealing or obturating method and apparatus for performing the various steps of said method are disclosed. Means for preparing a root canal for filling are disclosed which include instruments for cleaning out the root canal and preparing the interior of the canal so that it includes a series of staged steps which grow progressively larger from the apical end of the tooth to the crown. Unique finishing instruments are provided with a cross-sectional configuration such that they will provide the progressively larger steps. Also disclosed is a method and apparatus for sealing the root canal thus prepared, which includes provision of the gutta percha cones of particular configuration adapted to substantially conform to the internal stepped configuration within the root canal. Also disclosed is a combination cone which in itself is composed of a series of cones having progressively increasing diameters so as to be capable of sealing a plurality of steps in the canal. Improved means for inserting the cones into the root canal and assuring complete sealing thereof are also provided.

United States Patent [191 Malmin [4 1 Dec.24, 1974 ENDODONTIC OPERATINGAND SEALING METHOD AND APPARATUS THEREFOR [76] Inventor: Oscar Malmin,127 E. Wayne Ave.,

Akron, Ohio 44301 [22] Filed: Nov. 13, 1972 [21] Appl. No.: 305,973

Primary Examiner-Robert Peshock Attorney, Agent, or FirmFreeman & Taylor[57] ABSTRACT An endodontic operating and sealing or obturating methodand apparatus for performing the various steps of said method aredisclosed. Means for preparing a root canal for filling are disclosedwhich include instruments for cleaning out the root canal and preparingthe interior of the canal so that it includes a series of staged stepswhich grow progressively larger from the apical end of the tooth to thecrown. Unique finishing instruments are provided with a crosssectionalconfiguration such that they will provide the progressively largersteps. Also disclosed is a method and apparatus for sealing the rootcanal thus prepared, which includes provision of the gutta percha conesof particular configuration adapted to substantially conform to theinternal stepped configuration within the root canal. Also disclosed isa combination cone which in itself is composed of a series of coneshaving progressively increasing diameters so as to be capable of sealinga plurality of steps in the canal. Improved means for inserting thecones into the root canal and assuring complete sealing thereof are alsoprovided.

2 Claims, 21 Drawing Figures ENDODONTIC OPERATING AND SEALING METHOD ANDAPPARATUS THEREFOR RELATED APPLICATIONS This application is animprovement on and an expansion of the principles set forth inApplicants copending application entitled Endodontic Operating Systemfiled July 26, 1971, as Ser. No. 165,923, and Endodontic Sealing Systemand Apparatus filed Dec. 30,1971, as Ser. No. 213,993.

BACKGROUND OF THE INVENTION This invention, in general, relates to anendodontic root canal preparation method and the apparatus therefor, aswell as to an endodontic sealing method to be operated in conjunctionwith the operating method and again the apparatus for carrying out themethod.

DESCRIPTION OF THE PRIOR ART The following patent prior art is known toApplicant: Siegel, U.S. Patent 3,358,826; Saffro, U.S. Patent 3,562,913.

In addition to the aforementioned patent prior art, Applicant is awareof various forms of pluggers or applicators for endodontic sealing work,as well as reamers, broaches, etc., for preparing root canals. None ofthe devices known to Applicant has the capability of providing completesealing with the consistency, reliability, and accuracy of the methoddisclosed herein.

SUMMARY OF THE INVENTION It has been found that the preferred method ofinternal preparation of a root canal of a tooth and the preparation ofthat canal so as to obtain the highest possible degrees of totalobturation based upon the anatomical form can be achieved by firstpreparing the root canal in conventional fashion with a breach and areamer which gives a tapered effect to the canal.

It has then been discovered that by providing a series of progressivelylarger cross-sectional finishing instruments, it is possible, beginningat the apical end of the tooth, to provide a series of steps orprogressively larger diameter ledges toward the crown of the tooth. Suchledges differ from conventional forms of preparation in that force isdistributed laterally, thereby sealing accessory canals rather thanexerting full pressure in the apical foramen thereby extruding fillingmaterials into the tissues surrounding the tooth.

It has further been found that once the root canal has been prepared inthis fashion, improved sealing and obturation can be achieved byproviding cones of gutta percha or similar material which substantiallyconform to the internal configuration of the canal once it has beenprepared as above-noted.

It has been found that this can be accomplished either by utilizing aplurality of progressively larger cones or by using a unique combinationcone which is unitary but has progressively larger diameters thereon.

It has also been found that placement of the cones can be improved byproviding them with an integral wire member or shank, and uniqueplacement and separation forceps can be utilized to implace the cones,following which appropriate ultrasonic condensing instruments such asdisclosed in Applicants co-pending application, Ser. No. 213,993, can beused to obtain the greatest possible degree of obturation.

Accordingly, production of an improved endodontic operating and sealingmethod and apparatus therefor becomes the principal object of thisinvention, with other objects thereof becoming more apparent upon areading of the following brief specification and claims considered andinterpreted in view of the accompanying drawings.

OF THE DRAWINGS:

FIG. 1 is a cross-sectional view of a tooth showing a typical rootcanal.

FIG. 2 is a cross-sectional view similar to FIG. 1 showing a broach inplace within the tooth.

FIG. 3 is a view similar to FIGS. 1 and 2 showing a measurementinstrument such as disclosed in Applicants earlier co-pendingapplication, Ser. No. 165,923, referred to above.

FIG. 4 is a similar cross-sectional view showing a reamer similar tothat disclosed in Applicants earlier co-pending application, Ser. No.151,475.

FIG. 5 is a cross-sectional view showing a root canal which has beenprepared in staged steps in accordance with the teachings of theinvention.

FIG. 6 is a perspective view of an apical finishing tool such as wouldbe utilized to prepare the canal as shown in FIG. 5.

FIG. 7 shows a plurality of possible alternative cross sections for theinstrument of FIG. 6.

FIG. 8 is a cross-sectional view of gutta percha cones intended to beutilized in conjunction with the present invention.

FIG. 9 shows a typical hand-operated type of gutta percha cone which canbe used in a root canal prepared in accordance with the teachings ofthis invention.

FIG. 10 is an elevational view showing one of the cones of FIG. 8 and aninstrument for inserting or placing the same.

FIG. 11 is an elevational view showing a plurality of variations forcones such as shown in FIG. 8.

FIG. 12 is a cross-sectional view of a combination cone in elevationwhich has a plurality of different diameters.

FIG. 13 is a perspective view of a variation of the combination cone.

FIG. 14 is a cross-sectional view of a modified combination cone.

FIGS. 15 and 16 are perspective views of applicator forceps adapted tolocate cones such as shown in FIGS. 11, 12, and 14 in the root canal.

FIG. 17 is a cross-sectional view of the first step of the sealingoperation with one mini-cone in position and. an ultrasonic condensinginstrument applied thereto.

FIG. 18 is a view similar to FIG. 17 showing a still further progressionof the sealing process.

FIG. 19 is a cross-sectional view which shows the tooth with the rootcanal completely obturated by use of the cones.

FIGS. 20 and 21 are cross-sectional views showing a root canal preparedin a modified fashion.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning first then toFIG. 1, it will be noted that FIG. 1 illustrates a sectional view of atypical tooth T having a root canal R therein. The canal R stretchesfrom its apical end A to its coronal end C.

The method of treatment disclosed is perhaps best explained by astep-by-step approach, and accordingly FIG. 1 shows the tooth beforetreatment, with subsequent views illustrating the steps of the methodand the instrumentation for carrying it out.

Turning next to FIG. 2, the tooth of FIG. 1 is shown with a conventionalbroach inserted therein. This broach 10 will have a barb-like operativeend 12 and an apical end 11 and will be utilized initially to remove thepulp or remaining pulp remnants in a gross manner and to roughly finishthe interior of the root canal R.

FIG. 3 illustrates the same tooth T with a measurement instrument suchas illustrated in applicants earlier filed application, Ser. No.165,923. The measurement method and apparatus is fully disclosed in thatapplication, but it should be noted that once the measurement instrumentis inserted, an X-ray is taken to determine the working length desiredfor the root canal. Once this length has been determined, a reamer 22,such as shown in FIG. 4, will be employed with a stop 22a, as disclosedagain in applicants earlier application, being applied to the head. Aspointed out in that application, once the stop is secured to the head,it will bottom on the crown of the tooth and limit the working length ofthe root canal as predetermined.

It should be understood that the smallest diameter reamer is usedinitially and that a plurality of progressively larger diameter reamerswill be used until resistance to the reaming action is observed by thedentist. At that time the operation of the reamer will be continueduntil all resistance to the largest instrument utilized has beenremoved. Thus the canal will have been opened and cleaned and will havea fairly uniform taper from a largest dimension at the coronal portionof the canal to a narrowest dimension at the apical end thereof.

Turning next then to FIGS. 5 and 6 for the next steps in the method, itwill be noted that an apical finishing instrument is disclosed. Thisinstrument has a blade 31 and a handle 32. In the form illustrated inFIG. 6, the cross sectional configuration of the blade is substantiallysquare. FIG. 7, however, illustrates alternatives such as triangular in33, hexagonal in 34, octagonal in 35. Also, while the instruments 30,31, 33, 34, and 35 are illustrated as having straight side walls, it ispossible to undercut the walls of the various crosssectional instrumentsas shown in 36, 37, 38, and 39 by hollow grinding them. It should alsobe noted that the cross-sectional configurations illustrated are for thesake of illustration only and are not intended to be exhaustive.

Referring again then to FIG. 5, it will be noted that FIG. 5 shows theend result of utilization of apical finishing instruments such as 30.Thus it will be seen that starting at the apical end A of the canal, aseries of progressively larger steps 21, 22, 23, 24 are provided.

Thus in operation the canal would be prepared as shown in FIGS. 1through 4 by use of conventional instruments.

Following this, the smallest diameter apical finishing instrument 30,which corresponds in diameter to the last reamer used, would be insertedinto the canal and utilized to create the first stage step indicated at21 and which may be called the apical seal step. It should be noted thatthis first step will be spaced from the ultimate apical end A of thecanal as shown in FIG. 5, with this distance normally being about onemillimeter from the end of the working length established by themeasurement instrument shown in FIG. 3.

Following this, succeeding steps 22, 23, for example, are obtained byutilizing progressively larger diameter instruments such as 30. In thisregard only one size has been illustrated, with it believed to beapparent that greater diameters could be provided. In this fashion aseries of progressively larger openings are provided throughout thelength of the canal creating a ledge or step at each stage andultimately ending at the widest diameter, as indicated at 24.

In practice, starting with the first step at 21, each succeeding step iscreated by withdrawing 3 millimeters and reaming the canal to asucessively larger diameter, although precise measurements do not form apart of the invention with that depending upon the anatomy of the rootcanal system and the operators preference.

The end result will be to provide a root canal prepared along the linesshown in FIG. 5. It should also be noted that the widths in questionhave been exaggerated for purposes of illustration, with it beingunderstood that all of the components are considerably exaggerated forthat purpose also. The advantage of this final intra-radicularpreparation form is that positive ledging serves to transfer forcelaterally thereby sealing lateral or accessory canals more effectivelythan present preparation forms. Further, such positive ledging severs toavoid the entire condensing or filling force from forcing the fillingmaterials through the apical foramen and into the surrounding tissueswith the resulting irritation and pain that commonly occurs in presentmethods.

FIGS. 8 and 10 illustrate one method of doing this. Thus FIG. 8 shows agutta percha plug 43 having a stepped end at 43a. FIG. 8 also shows aslight variation of this in which the corners are rounded as at 460 and46b.

When utilizing this type of cone or plug, it is simply necessary to usethe hand instrument 50 by grasping the handle 51 and inserting theprojecting end 52 into the cone. At this time the cone would be placedinto the first staged step or apical seal step 21 At that point,suitable condensing devices as shown in Applicants copendingapplication, Ser. No. 213,963, could be utilized to tamp the plug 43 inplace and assure complete obturation of the primary canal and thelateral canals. In this regard the cone would have a slightly smallerdimension than that of the step 21 which would be compensated for by thecondensing and packing operation.

FIG. 11 also shows other means for implacing the mini-cone in theprepared canal. Thus the numeral indicates a cone of the type shown inFIG. 8, which has a wire embedded therein and would be sitable for usewith the handle means disclosed in applicants earlier co-pendingapplication, Ser. No. 51,475 are now U.S. Pat. N0. 3,713,221 issued Jan.30, 1973.

The numeral 240 indicates a different form of the invention in which ahandle and stopping mechanism, such as shown in applicants earlier filedapplication, Ser. No. 165,923 and now U.S. Pat. No. 3,772,791 issuedNov. 20, 1973, are employed.

The numeral 340 indicates formation of a handle by crushing orflattening the projecting wire at 341 to provide a gripping surface.

To the same effect, 440 indicates a conventional nail, brad, or pin withan enlarged head 441 which'would facilitate gripping.

Finally, 540 indicates application of the cone by utilizing aconventional root canal reamer as a mechanism for implacing theminiature cone in the root canal.

It is also possible to use a cone such as shown in FIG. 9 where thedevice 40 has an elongate body 42, an enlarged head 41, and a coneportion 43. Portion 43 has a configuration matching apical step 21 andis connected to body 42 by a thin neck formed by cutting annular groove45 in the body. Once the apical cone is in place, the body is twisted sothat it breaks at the neck leaving the cone 43 in place.

Once the apical seal cone is in place, utilization of a plurality ofincreasing diameter cones of the general types shown in FIGS. 8, 10, and11 will result in ulti mately filling the root canal. It has been foundthat further improved results can be obtained by utilizing a fullyintegrated combination cone such as shown in FIG. 12. Thus in FIG. 12such a cone 150 is composed of a series of cones which have aprogressively increasing diameter, going from the smallest diameter at151 to the largest at 154, with these diameters corresponding to thesteps in the root canal prepared as shown in FIG. 5. An elongate handle155 is provided of some rigid material, with a groove 156 provided onits outboard end to be engaged by the forceps shown in FIGS. 15 and 16which will be described later.

Thus in order to utilize this type of cone, forceps 60 will be employed.The forceps include a pair of opposed handles 61, 62 pinned as at 63 andinterconnected by spring 64a so that they would normally be urged to theposition of FIG. 15. The handle 61 has an opening 61a thereon, and alatch 64 is secured to the handle 62 and projects through the opening61a so that the forceps can be locked in any predetermined position.

Provided on the forward end of the forceps is a locking latch 65 with aseparating tube 66. It will be noted that the shank 55 of the cone 50has been secured in place. When it is desired to insert the cone 50 inthe tooth, it is merely necessary to insert it into the canal, followingwhich the handles 61 and 62 are brought together against the force ofthe spring 64a. At this point the separating tube 66 will force theendmost cone off the handle 55 and into place the tooth, following whichcondensing by the normal ultrasonic instruments is accomplished asdescribed above.

It will also be noted that latch 64 has a plurality of teeth thereonwhich engage the edge of opening 61a so that by correlating the space ofthe teeth to the depth of cones 51, 52, 53, and 54 compression of thehandles and successive engagement of the teeth will dislodge theindividual cones as required.

FIGS. 17 and 18 show progressive steps of the sealing method. Thus FIG.17 shows the apical sealing cone which could be the form shown in FIGS.9 and 10 or the form shown in FIG. 12. The apical cone has been placedin place in the first step 21, and the condensing point 70 is beingapplied to it.

In FIG. 18 condensing of the first cone has been completed, and it willbe noted that while the cone is initially slightly undersized withrelation to the step 21, the condensing action spreads it so that itdoes, in fact, fill the space. In FIG. 18 the second cone, such as 52,has been inserted, and again condensing head 70 is being appliedthereto.

FIG. 19 shows a completed root canal in which all of the successivelylarger cones have been separately implaced and condensed so that theentire canal structure I is completely obturated. Following this, ofcourse, the appropriate sealing or filling material would be implaced inthe coronal portion of the tooth, following which the root canal therapywill have been completed.

FIGS. 13, 14, 20, and 21 illustrate an alternative and more simplifiedmethods of sealing root canals.

Thus while the method shown above is satisfactory and would, in fact, bethe ideal method of obturating a root canal system, it has beendiscovered that an even more simplified method could be employed whichwould result in a saving of time and effort and thereby increase theefficiency of the operator.

Thus referring to FIGS. 20 and 21 and assuming that the root canal hadfirst been prepared as shown in FIGS. 1 through 4 and describing above,the first step would be to apply the apical finishing instrument, suchas shown in FIG. 6, to provide the first or apical seal step 121. Thesecond step 122, however, would be prepared by using the largestdiameter instrument which would provide an uninterrupted root canalpreparation from the level of the step 122 to the coronal portion oropening of the tooth.

When this form or preparation is utilized, it is possible to employdifferent cone constructions.

Thus referring to FIG. 13, it will be seen that a modified combinationcone is employed which has an apical sealing cone 91 and a plurality ofadditional cones 92, 93, 94, each of which is interconnected by arelatively thin central core 95 of gutta percha and has a graspingportion 96 at the opposed end. This type of cone makes it possible toinsert, for example, the apical cone 91 into place, and then bytwisting, the thin core 95 will be broken. Following this, thecondensing operation can take place and then the cone 92 will beimplaced and a similar operation will ensue until all of the cones havebeen implaced and condensed.

FIG. 14 shows yet another form of combination cone 100 with an apicalfinishing member 101 and a plurality of cones 102, 102. The cones areall connected by a central metal core pin 104. In this way again theapical cone 101 is implaced, and the device is withdrawn, followingwhich the condensation operation takes place and the sequence of eventsis similar to that described above.

It should be noted that the walls of the canal shown in FIGS. 17 and 18are tapered from a minimum diameter adjacent step 121 to a maximumdiameter at the coronal end.

Depending upon the configuration of the finishing instrument 30, thesewalls could also be straight. A similar differennce will be notedbetween the combination cones 90 and 100 shown in FIGS. 13 and 14 inwhich in FIG. 13 the cones are of increasing diameter to accommodate ancanal which has been prepared with an increasing diameter, while in FIG.14 the cones are of identical diameter as would be the case when thewalls of the canal are parallel.

While a full and complete description of the invention has been setforth in accordance with the dictates of the Patent Statutes, it shouldbe understood that modifications can be resorted to without departingfrom the spirit hereof or the scope of the appended claims.

What is claimed is:

1. A substantially compressible gutta percha endodontic sealing cone foruse in root canals, comprising opposed end with an offset reduceddiameter projection thereon; a plurality of secondary finishing membersof substantially equal dimensions arranged in series from the base endof said apical finishing member; and a handle removably disposedcentrally of said finishing members; said handle extending from saidapical finishing member through said secondary finishing members andprojecting from the last said secondary finishing member.

1. A substantially compressible gutta percha endodontic sealing cone foruse in root canals, comprising an elongate substantially cylindricalbody with first and second ends; said body having a plurality of offsetshoulders at spaced intervals along its length to form progressivelylarger segments from said first to said second ends; and a handleprojecting from said second end and being removably disposed centrallyof said body and extending from a point adjacent said first end of saidbody.
 2. A substantially compressible gutta percha endodontic sealingcone for use in root canals, comprising an apical finishing memberhaving a base end and an opposed end with an offset reduced diameterprojection thereon; a plurality of secondary finishing members ofsubstantially equal dimensions arranged in series from the base end ofsaid apical finishing member; and a handle removably disposed centrallyof said finishing members; said handle extending from said apicalfinishing member through said secondary finishing members and projectingfrom the last said secondary finishing member.